Abstract: I will describe a Hayden & Preskill like setup for both maximally chaotic and submaximally chaotic quantum field theories by acting on the vacuum with an operator in a Rindlerlike wedge R, and transferring a small subregion I of R to the other wedge. The chaotic scramblingdynamics of the QFT Rindler time evolution reveals the information in the other wedge. Theholographic dual of this process involves a particle excitation falling into the bulk and crossinginto the entanglement wedge of the complement to r = R\I. With the goal of studying thelocality of the emergent holographic theory, I will compute various quantum information measureson the boundary that tell us when the particle has entered this entanglement wedge. In amaximally chaotic theory, these measures indicate a sharp transition where the particle entersthe wedge exactly when the insertion is null separated from the quantum extremal surfacefor r. For sub-maximally chaotic theories, there is instead a smoothed crossover at a delayed timegiven in terms of the smaller Lyapunov exponent and dependent on the time-smearing scaleof the probe excitation. I will discuss theextent to which these results reveal properties of the target of the probe excitation as a “stringyquantum extremal surface” or simply quantify the probe itself thus giving a new approach tostudying the notion of longitudinal string spreading.